CVE-2020-11239
📋 TL;DR
This CVE describes a use-after-free vulnerability in Qualcomm Snapdragon chipsets when handling DMA buffer imports. Attackers could exploit this to execute arbitrary code or cause denial of service on affected devices. The vulnerability impacts a wide range of Qualcomm-powered devices including smartphones, IoT devices, automotive systems, and wearables.
💻 Affected Systems
- Snapdragon Auto
- Snapdragon Compute
- Snapdragon Connectivity
- Snapdragon Consumer IOT
- Snapdragon Industrial IOT
- Snapdragon Mobile
- Snapdragon Voice & Music
- Snapdragon Wearables
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full device compromise allowing remote code execution with kernel privileges, potentially leading to complete system takeover, data theft, or persistent backdoor installation.
Likely Case
Local privilege escalation allowing an attacker to gain elevated privileges on the device, potentially leading to data access, further system compromise, or denial of service.
If Mitigated
Limited impact with proper security controls like SELinux/AppArmor, kernel hardening, and privilege separation, potentially reducing to denial of service only.
🎯 Exploit Status
Exploitation requires local access to the device. The vulnerability is in DMA buffer handling which requires specific conditions to trigger.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Refer to device manufacturer updates - patches were released in January 2021 security updates
Vendor Advisory: https://www.qualcomm.com/company/product-security/bulletins/january-2021-bulletin
Restart Required: Yes
Instructions:
1. Check with device manufacturer for available security updates. 2. Apply the latest firmware/security patch from your device manufacturer. 3. Reboot the device after update installation. 4. Verify the patch level matches or exceeds January 2021 security patch level.
🔧 Temporary Workarounds
Restrict DMA buffer access
linuxImplement kernel-level restrictions on DMA buffer operations through security modules
echo 1 > /proc/sys/kernel/dma_restrict
# Note: This is example syntax - actual implementation varies by kernel
🧯 If You Can't Patch
- Implement strict application sandboxing and privilege separation
- Deploy kernel hardening measures like SELinux/AppArmor with restrictive policies
🔍 How to Verify
Check if Vulnerable:
Check device security patch level - if before January 2021, likely vulnerable. Check with device manufacturer for specific vulnerability status.Check Version:
On Android: Settings > About phone > Android security patch levelVerify Fix Applied:
Verify security patch level is January 2021 or later. Check device manufacturer's security bulletin for confirmation.📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- DMA-related error messages in kernel logs
- Unexpected process crashes with memory access violations
Network Indicators:
- Not applicable - local vulnerability
SIEM Query:
source="kernel" AND ("DMA" OR "use-after-free" OR "kernel panic")